Fluid pressure braking system



i' June 6, -l9;39. I *A. A. LOWEKE 5,

v I I FLUID PRESSURE BRAKING SYSTEM Filed Sept. 27, 1957 2 Sheets-Sheet1 N, N N

' 'INVENFOR. v 9 020416. Lows/reasmgz 4 444M ATTORNEY;

'June 6, 1939. A. A. LOWEKE 2,161,304

FLUID PRESSURE BRAKING SYSTEM .Filed Sept. 27, 1937 2 Sheets-Sheet 2 QINVENTOR gaze/v 67. Lows/r:

I ATTORNEYS.

Patented June 6, 1939 "UNITED STATES PATENT OFFICE -i t 2,161,304, q

FLUID PRESSURE BRAKING'SYSTEM Aaron A. Loweke, Detroit, Mich, assignorto li ydraulic Brake Company, Detroit, Mich, a corporation ofCaliforniav Application September 27, 1937, SerialNo. 165,806

p I 6 Claims. (01. 188.-265)' I This invention relates to fluid pressurebraking type -are mounted for rotation on the respective systems. axles.I I v Broadly the invention comprehends a fluid A power plant orinternalcombustion-engine pressure braking system operative toeffectively 22 supported on the framehas associated therea'ctuate abrake, or aplurality of brakes, and to with a transmission 24 having itsmain shaft 26 retain the brake or brakes in applied position connectedby a driven shaft 28 to thedifferential =without further attention onthe part of the of the rear axle l8, and associated with themainoperator. I I I shaft is a brake of conventional type. v

In the illustrated embodiment of the inven- Preferably the brakeincludes a flxed. support tion, a fluid pressure producingdevice hasconor backing plate'30, suitablysecured'tolthe housnected thereto afluid pressure actuated motor ing of the transmission 24, 'a'drurn .32,associated arranged for the actuation of the friction elewith thebacking plate mountedpnj and for rotament of a brake associated with themain drive tion with the mainshaft 126, a-pair of coneshaft of a motorvehicle. sponding friction elements or shoes 34 pivoted on An object ofthe invention is to provide a fluid the'b'acklng plate, aretractilespring 36 connectpressure braking system'operative to effectively ingthe shoes, and a fluid pressurepactuated apply a brake and to retain thebrake in'applied motor 38 mounted on thebacking: plate-between Iposition. v t y the shoes and operative to; actuate the shoes into 7 IAnother object of thelnvention is to provide. engagementwith the drumagainst the resistance 9 a fluid pressure braking system operative toefof the retractilespring. J fectively apply and retain a brake inapplied Afi d p jess l e producing device Ill-Sui position and toquickly release the brak'e'at the supported on the frame includes areservoir 42 will of the operator. having a filling opening normallyclosed as by \Another object of the invention is to provide a a plug 46having openings 48"forventing the fluid pressure braking systemoperative to step reservoir to the atmosphere/Formed at the base up thepressure on the fluid in the system, to of the reservoir-is a cylinder50 openat one end retain the pressure constant as long as desired, andclosed at its other end as 'by a head 52 havand to quickly release thepressure at the will ing a discharge port 54 controlled by acheck of theoperator. valve 58 for inhibiting retrograde movement of A feature ofthe invention is a fluid pressure the fluid. The cylinder also hasarranged in its producing device including a reservoir, a cylinwallspaced ports 58 and 60 providing communider supplied therefrom having acontrolled discations betweenthe cylinder and the reservoir.

charge port, a piston reciprocable in the cylin- The discharge port ofthe cylinder has conder, and an actuator for the piston having a, nectedtheretobeyond the check valve 56 a twochamber therein connected to thereservoir and way fitting 62, and one branch of this fitting is m thecylinder beyond the discharge port, and connected by a fluid pressuredelivery pipe 64 to means in the actuator for controlling the flow of eflu d p ess e t d motor 33 0f the brake, fluid through the chamber. thepurpose of the other-branch of the two- Other objects and features ofthe invention way fitting 62 will hereinafter appear.

" will appear from'the following description taken A P s 56 reciprocablein the y inder s held 40 in connection with the drawings forming a partagainst displacement by 3- washer seated on of s Specification, and inan annular shoulder in the open end of the cyl- Fig 1 is schematic Viewof a motor vehicle inder and secured in place as by a retaining ring 7 45 hassis illustrating the invention as applied; I "Seated groovgx t Wallof the 'cylmder' The piston has a head 12', a reduced body'portion 14providingjin conjunction with thewall' of the cylinder an annularchamber 16 communicating with the reservoir by w y 'r the port 58, and askirt 18 having thereon a sealing cup 80 for in- Fig, 2 is a verticalsectional view of the brake; and

g, Fig. 3 1m vertical sectional view of the fluid pressure producingdevice.

5Q R n t0 the drawings for more c hibiting seepage 'of fluid from thecylinder.

I details of the invention, l0 represents the frame head 12 of t i ton aplurality of Of a motor Vehicle c fl frame is D- spaced passages 82therethrough providing comported on front springs l2 and rear springs 14munica'tions between the annular chamber 16 suspended respectively froma front axle i6 and and that portion of' the cylinder forward of the arear axle II, and wheels 20 of conventional piston.'Acollapsiblesealing/cup 84 seated on the 55 head I2 controls thepasages, and a spring I.

interposed between the cup and the head 52 of the cylinder serves toretain the cup against displacement and also to return the piston to itsretracted position.

The piston has a recess 88 in its back for the reception of one end of athrust pin DI, and the other end of the thrust pin has 'thereon afltting 92 connected as by a flexible boot I to the open end of thecylinder forthe exclusion of dustfrom the cylinder. The fltting 82 isconnected as by a clevis to an operating lever 8i pivotally mounted on abracket 08 formed integral with the cylinder II.

The operating lever It has an axial bore Ill, a portion of which has anincreased diameter providing a passage I02 having a port I connected asby a flexible tube II! to an opening III in the wall of the reservoiradjacent to the top thereof, and another portion of this axial bore I isincreased in diameter to provide a chamber III communicating directlywith the passage "2 and opening at the bottom of the lever.

A plug 2 secured in the open end of the chamber III has a concentricextension III, and the plug and its extension are bored to provide anaxial passage Iii controlled as by a two-' way valve. As shown, a rubberwasher II! seated on the extension supports an annular disk I2! having aconcentric sleeve I22 depending therefrom into the passage III, and thesleeve is slotted on its periphery as at I24 for the pas.- sage of fluidwhen the disk is raised from its seat.

A cage I2! secured to the extension has openings I2l therethrough forthe passage of fluid, and a spring I" interposed between the'cage andthe disk I2l yieldin'gly retains the disk on its seat. The sleeve I22 isnormally closed by a ball I22 urged to its seat by a spring Ill seatedon a fltting I26 threaded in the outer end of the plug and connected asby a flexible tube I" to the branch fltting i2.

A rod I, extending through the bore III, the passage I02, and thechamber III, has one end supported on the ball I32 and its other end prjecting from the top of the operating lever and provided with a buttonI42, and a sealing cup I 44 seated on the annular shoulder at theJunction of the here I and the passage I02 is held against displacementby a spring I" interposed between the cup and the shell I28.

In a normal operation, upon actuation of the operating lever 96, forceis transmitted therefrom through the thrust pin 9. to the piston it,resulting in movement of the piston on its compression stroke. Duringthe initialv movement of the piston on its compression stroke thesealing cup 84 on the head of the.piston covers the port, andthereafter, as the piston moves on its compression stroke, fluid in thecylinder II forward of the piston is displaced therefrom through thedischarge port 54, past the valve and through the fluid pressureactuated motor 30, causing energization of the motor, resulting inactuation of the friction elements or shoes 34 into engagement with thedrum 22 against the resistance of the retractile spring 8.

Because ofthe valve 5.6, inhibiting retrograde movement or the fluid,the brake is retained in applied position without further attention onthe part of the operator or by the employment of mechanical meansserving to retain the actuating lever in depressed position, and,because of a,1o1,so4

this condition, should it be found desirable to apply the brake withincreased force, the operator may repeatedly actuate the operating leverso as to build up pressure in the fluid pressure delivery pipe GI andthe motor 38. The pressure built up in the delivery pipe and motor islimited to the extent of the load on the spring I", urging the two-wayvalve to its seat, so that excessive pressure tending to rupture thedelivery pipe GI may be avoided. When excessive pressure is imposed onthe fluid in the system, the

. two-way valve opens, whereupon a small quantity of fluid is returnedto the reservoir.

When it is desired to effect an immediate release of the brake, eitherat the time of applying the brake or subsequently thereto, the operatorpresses on the thumb button I42 and this force is transmitted throughthe rod I to the ball valve I32, resulting in opening the valve,whereupon the fluid in the motor 38 and the fluid pressure delivery line64 is returned under the through the passages 82 in the head of thepis-.

ton, past the cup 84, into that portion of the cylinder forward of thepiston, completely filling the cylinder.

Although this invention has been described in connection with certainspeciflc embodiments, the principles involved are susceptible ofnumerous other applications that will readily occur to persons skilledin the art. The invention is, therefore, to be limited only by the scopeof the appended claims. Y

Having thus described the various features of the invention, what Iclaim as new and desire to secure by Letters Patent is:

1. A fluid pressure braking system comprising a reservoir, a cylindersupplied therefrom having a dis-charge port, a check valve controllingthe discharge'port, a piston reciprocable in the cylinder, an actuatorfor the piston, a fluid pressure actuated motor connected to thecylinder beyond the check valve, a brake actuated by the motor, and arelief valve in the actuator connected to the reservoir and to thecylinder beyond the check valve.

2. A fluid pressure braking system comprising a' reservoir, a cylindersupplied therefrom having a discharge port, a check valve controllingthe discharge port inhibiting retrograde movement of fluid, a pistonreciprocable in the cylinder, an actuator for the piston, a fluidpressure actuated motor connected to the cylinder beyond the checkvalve, a brake actuated by the motor, a relief valve. in the actuator, afluid delivery means connecting the relief valve to the reservoir, otherfluid delivery means connecting the relief valve intermediate the checkvalve and the motor, and means carried by the actuator for opening therelief valve.

in the actuator connected to the reservoir and to the discharge port ofthe cylinder beyond the check valve, a relief valve in the chamber, andmeans slidable in the actuator for opening the relief valve.

4. A fluid pressure system comprising a fluid pressure producing device,an actuator therefor, a fluid pressure actuated motor connected to thedevice, means for maintaining fluid pressure in said motor, means,including said actuator, forming a by-pass conduit around said firstnamed means, and means for manually controlling fluid flow through saidby-pass. x,

5. A fluid pressure system comprising a fluid pressure producing device,a hollow lever for actuating said device, a fluid pressure actuatedmotor connected to the device, means for maintaining fluid pressure insaid motor, and means comprising said hollow lever and a flexibleconduit forming a by-pass around said first named means, a valve in saidhollow lever controlling said bypass, and a rod in said hollow lever foroperating said valve. I

6. A fluid pressure system comprising a reservoir, a cylinder suppliedtherefrom, a piston reciprocable in the cylinder, an actuator for thepiston, a fluid pressure actuated motor connected to the cylinder, acheck valve intermediate the cylinder and motor, means, including saidactuator, constituting a by-pass for connecting the reservoir with themotor side of check valve, 8. relief valve in said actuator, and meansfor manually operating said relief valve.

AARON A. LOWEKE.

